1. Air Quality
Half of the air in the cabin of all modern aircrafts comprise of the fresh air entering inside through the engines. The air coming in is taken in after being filtered by the air filters called HEPA. All cabin air is replenished every 2-3 minutes. In other words, the cabin air is completely refreshed 20-30 times per hour. In this respect, the cabin environment has much more clean and refreshed atmosphere than the house or office environment. Organic compounds, microorganisms , the amount of carbon monoxide , carbon dioxide and ozone in the cabin air do not pose a problem in terms of health.
The HEPA filters prevent the bacteria,fungi,certain viruses and other particles from entering in . Despite certain diseases known to be transmitted in aircraft cabins, it is thought that mostly person-to-person transmission, rather than by cabin filter system, occurs when the sick person coughs and sneezes. For this reason, especially the persons with communicable diseases such as tuberculosis must not fly unless the mentioned diseases are under control. Passengers should definitely cover their mouth and nose by handkerchief or by their arm while coughing and sneezing during the flight.